Helmeted lock ring for a sender module closure system for a fuel tank

ABSTRACT

An improved sender module closure system for providing a reliable, sealed interface between a sender module and a fuel tank at the access port thereof, includes an interfacing ring set composed of a base ring and a helmeted lock ring. The base ring is permanently connected to the fuel tank at the access port, and has a plurality of upstanding lock fingers. The helmeted lock ring is a separate piece, composed of a lock ring component and an integrally connected helmet component. The lock ring component has a plurality of finger apertures, one for receiving each lock finger. The helmet component protectively covers the sender module and has helmet apertures for external access to connectors of the sender module.

TECHNICAL FIELD

The present invention relates to automotive fuel tanks, particularly the closure system used for sealingly interfacing therewith the sender module, and more particularly to a helmeted lock ring therefor.

BACKGROUND OF THE INVENTION

Automotive fuel tanks have an access port at an upper wall thereof through which fuel passes and various components are placed, as for example a fuel depth sensor and a fuel pump. Supporting the various components at the access port in sealing relation with the fuel tank is a sender module, which is commonly of plastic construction.

Historically, the integrity of the seal of the sender module with respect to the fuel tank has been a matter of continuing engineering interest. One of the driving forces behind this interest is ever tightening government vapor emissions rules, wherein emissions concerns may be amplified by manufacturing tolerance variations. An additional cause for engineering interest is the need to increase the cross-sectional size of the access port as additional components are added to the list of components carried by the sender module (ie., from a typical 95 mm to 130 mm). As the size of the access port increases, issues of reliable sealing become more critical, especially in view of crashworthiness vis-a-vis the fuel tank. An interesting added feature to the foregoing considerations is the direction the industry is taking to replace metal fuel tanks with polyethylene fuel tanks.

Accordingly, what has been needed in the art is a closure system for providing a reliable, sealed interface between the sender module and the fuel tank at the access port thereof. A known fuel tank sender module closure system which has proven extremely successful in this regard is depicted at FIGS. 1 through 15.

Referring firstly to FIGS. 1 through 4, an overview, in general terms, of the structural and operational facets of the prior art sender module closure system 100 will be discussed. The prior art sender module closure system 100 is interfaced with respect to a fuel tank 102, and a sender module 104. The fuel tank 102 is of a multi-layer polyethylene construction, and has a circular access port 106. Adjacent the access port 106 is a seal seat groove 108 having a floor 108F upon which a resilient seal 110 seatably rests. The sender module 104 is of plastic construction and carries numerous components which access the interior of the fuel tank 102. The sender module 104 has an annular flange 114 which lies flatly over the resilient seal 110, and further has an annular lip 116 which is received by the access port 106 and serves to abuttably locate the sender module with respect to the perimeter of the access port. The annular flange 114 of the sender module 104 is pressed toward the fuel tank so as to compress the resilient seal 110 sealably between the floor 108F and the annular flange 114 by action of a mutually interfacing ring set 118 composed of a base ring 120 and a lock ring 122.

The base ring 120 has a plurality of upstanding lock fingers 124 spaced equally therearound, each lock finger having a laterally oriented lip 126 projecting radially inward toward a center of the base ring. As seen at FIG. 3, each lip 126 has a prestage ramp 128, a staging boss 130, a staging socket 132 and an over-travel boss 134. The base ring 120 further has an anchor portion 136 which is permanently attached to the fuel tank 102 during blow molding of the polyethylene during forming of the fuel tank. A preferred shape of the anchor portion 136 is an “S” shape, as shown at FIG. 2, wherein the lower section 136L is laterally oriented, the middle section 136M is upwardly oriented and has a plurality of embedment holes 138 (see FIG. 3), and the upper section 136U rests laterally in a base ring groove 140. A plurality of tabs 136T extend laterally outward and are embedded in the polyethylene of the fuel tank. The aforementioned lock fingers 124 upwardly extend from the upper section 136U so as to be upstanding in relation to the seal seat groove 108 and the fuel tank 102.

While the base ring 120 is an integrated component of the fuel tank 102, the lock ring 122 (depicted at FIG. 4) is an independent component which is separate from the fuel tank. The lock ring 122 has a plurality of finger apertures 142, one for receiving each lock finger 124. Each finger aperture 142 has an entry portion 142E for passing a respective lock finger therethrough and a lock portion 142L at which the lip 126 of the respective lock finger interferingly overhangs a lock shelf 144 of the lock ring 122. As shown at FIG. 2, each lock shelf 144 tangentially adjoins the lock portion 142L of its corresponding finger aperture 142, and has a medially located lock boss 146. An upstanding annular lug 150 is provided at the inner periphery 152 of the lock ring for stiffening, as well as for aiding location with respect to the sender module 104.

Referring now primarily to FIG. 2, operation of the prior art sender module closure system 100 will be generally described.

The sender module 104 is placed into the access port 106 such that the periphery thereof abuts the annular lip 116. With the resilient seal 110 seated at its seal seat groove 108, and the annular flange 114 resting upon the resilient seal, the lock ring 122 is placed thereover via the lock fingers 124 being received through the entry portion 142E of the finger apertures 142. The lock ring 122 is then rotated so that the flat 144F of each lock shelf 144 (see FIG. 12) is prestaged interferingly under its respective lock finger prestage ramp 128. The outer perimeter 122P of the lock ring 122 has a plurality of tool engagement features in the preferred form of notches 148 into which are interfaced with bosses 154 a of a bossed service tool 154 so as to effect the aforesaid rotation and/or to effect further rotation of the lock ring 122 relative to the base ring 120.

As the rotation ensues (referred to as “camming on”), each lock boss 146 slides along its respective staging boss 130 and seats at its respective staging socket 132. The seating of the lock bosses 146 in the respective staging sockets 132 causes the lock ring 122 to move toward the fuel tank 102. Accordingly, the resilient seal 110 is compressed (i.e., a compression of about 25 percent) so as to cause the resilient seal to seal between the floor 108F of the seal seat groove 108 and the annular flange 114 of the sender module 104. Over-travel is not permitted by the lock finger 124 abutting the end 142S (see FIG. 4) of its respective finger aperture 142, and each lock boss 146 tends to center at its staging socket 132 by cooperative action of the over-travel boss 134 and the staging boss 130 with respect to the lock boss 146 situated therebetween. The bossed service tool 154 may be again interfaced with the notches 148 so as to effect reverse rotation of the lock ring 122 (referred to as “camming off”) so that the sender module may be removed from the fuel tank.

Referring now additionally to FIGS. 5 through 15, further illustrative aspects of the prior art sender module closure system 100 will be detailed.

The base ring 120, seen at FIGS. 5 through 8 and labeled as described hereinabove, is composed of rigid galvanized and annealed (galvannealed) steel having a thickness of 2.0 mm and a protective coating, such as paint. As shown at FIG. 5, the inner diameter D₁ is 145.0 mm, and there are seven lock fingers 124, wherein the lips 126 thereof are all laterally oriented and project radially and laterally toward the center of the base ring, and wherein the edge 126E of the lips has an angle A₁ of 90.0 degrees relative to a radiant (see FIG. 7).

Each of the lips 126 is embossed to provide the prestage ramp 128, the staging boss 130, the staging socket 132 and the over-travel boss 134. As shown at FIG. 8, the width W of the lock finger is 27.61 mm, which corresponds to a tangential angle A₂ of 18.0 degrees; the angle A₃ of the staging boss is 20.0 degrees; the angle A₄ of the over-travel boss is 17.2 degrees; the angle A₅ of the staging boss side of the staging socket is 18.3 degrees; the distance S₁ between the apex of the staging boss and the center of the staging socket is 2.70 mm; the distance S₂ between the center of the staging socket and the apex of the over-travel boss is 4.70 mm; the staging ramp has a height H₁ of 8.80 mm; the staging boss has a height H₂ at its apex of 7.85 mm; the staging socket has a height H₃ at its center of 8.45 mm; and the over-travel boss has a height H₄ at its apex of 7.25 mm. Each lock finger has an upward taper at an angle A₆ of 4.15 degrees, and the lip thereof has a lateral (radial) overhang distance S₃ of 3.5 mm.

The lock ring 122, seen at FIGS. 9 through 11 and labeled as described hereinabove, is composed of rigid galvanized and annealed (galvannealed) steel having a thickness of 2.5 mm and a protective coating, such as paint. As shown at FIG. 9, the inner perimeter diameter D₂ is 125.25 mm, and there are seven finger apertures 142, having a tangential elongation angle A₇ of 37.56 degrees, with the lock portion thereof having a tangential elongation angle A₈ of 18.0 degrees. The radial cross-section C₁ of the entry portion of each finger aperture is 9 mm and the radial cross-section C₂ of the lock portion is 4 mm. The lock boss has a fore angle A₉ of 22 degrees; an aft angle A₁₀ of 45 degrees, and a height H₅ of 4.3 mm. The lock boss is located a distance S₄ of about 4 mm from the end of the aforementioned lock shelf 144 (at the entry portion 142E), thereby defining a flat 144F (see FIG. 12).

FIG. 12 shows the interaction between the staging socket 132 and the lock boss 146 when the lock ring 122 is locked relative to the base ring 120, as well as showing the relative placement of the prestage ramp 128, the staging boss 130 and the over-travel boss 134. It is seen that the lock boss 146 is seatingly positioned in the staging socket 132 akin to a “ball-and-socket” arrangement, in the sense that the “socket” is defined by the concave shape between the staging and over-travel bosses and the “ball” is defined by the convex shape of the lock boss.

FIG. 13A depicts the lock ring 122 “prestaged” with respect to the base ring 120. In this regard, the flat 144F of the lock shelf 144 is slipped abuttingly (interferingly) under the prestage ramp 128. This position may be obtained by hand movement of the lock ring 122 or via the bossed service tool 154. FIG. 13B shows the lock boss “staged” whereat the lock boss 146 is seated into the staging socket 132. As can be seen by comparison between FIGS. 13A and 13B, rotation of the lock ring 122 from the prestaged position to the staged position involves the lock bosses causing the lock ring to move vertically toward the fuel tank. This movement causes the above mentioned sealing compression of the resilient seal between the annular flange and the fuel tank.

FIGS. 14 and 15 depict further aspects of the locking of the lock ring 122 onto the base ring 120. As can be best seen at FIG. 14, the lip 126 interferingly overhangs the lock shelf 144. As can be best seen at FIG. 15, over travel of the lock boss 146 with respect to the staging socket 132 is prevented by each lock finger 124 striking the end 142S of the lock portion 142E of its respective finger aperture 142. At this position, each lock boss engages its respective over-travel boss, which engagement tends to center each lock boss into its respective staging socket. It is preferable that the contact location of the lock ring 122 with respect to the base ring 120 (when the lock ring is at the staged position) occurs with respect to a portion of the lock boss and the staging socket which is radially nearest the lock aperture (ie., about 4 mm radially inward from the lock portion 142L).

The following comments amplify upon the above recounted illustration.

The base ring 120 has seven lock fingers 18 degrees wide, and the lock ring 122 has seven symmetrically spaced lock bosses so that: a) load is dissipated into the anchor portion of the base, b) the lock ring 122 is cammed on without the lock fingers flexing, and c) there is a minimum distance between the prestage and staged positions.

The lock ring material thickness of 2.5 mm eliminates a phenomenon termed “potato chipping,” which refers to a ring bending between its engagement spokes. The annular lug 150 of the lock ring runs out 2.5 mm for eliminating a phenomenon termed “tee pee,” which refers to a ring bending up or down at the inside diameter relative to the outside diameter. The lock ring notches 148 are minimized so as to eliminate potato chipping and tee pee. The base ring material has a thickness of 2.0 mm so as to eliminate “ring flexing” between or at the lock fingers.

When the lock ring 122 is cammed on into the staged position, a “ball and socket” arrangement transpires, entailing a critical manufacturing of both a 2.5 mm radius “socket” and a 2.0 mm radius “ball.” The entire load dissipation of the ring set at the staged position occurs through the seven lock bosses which are equally spaced apart by 53.4 degrees (also referred to as “top dead center” of the “ball” locking into the “socket”), wherein the critical linear load carrying distance for this interface is 4.0 mm radially inward from the lock portion 142L of the finger aperture. To ensure maximum load transfer between the lock ring 122 and the lock fingers 124, the lock ring finger apertures are toleranced and narrowed so as to be as small as possible.

The shape of the lock fingers is a balance between three critical items: a) maximum strength, b) the allowance for an anti-reverse rotation feature, and c) the allowance for a “solid” discernable stop.

The “offset” W-shape associated with the staging boss, staging socket and over-travel boss of the lips is provided by two post-strikes which are put in during the finalization of the part, wherein a “lead” strike provides the staging boss, and a “follow” strike provides the over-travel boss, and wherein the position of these features relative to the center of the lip allows for two 17 to 18 degree angles which increase strength due to material processing.

A 1.0 mm radius on the underside of the base ring lock fingers prevents “finger flex” (a condition noted when the lock finger is bent up greater than 5 degrees), wherein if this radius is too large then installation torque increases will be noticed, and if this radius is 0 mm, then a stress riser will exist within in the part.

The size and placement of the base ring embedment holes play a significant role in ring strength, wherein the size and locations thereof are selected as a balance between three critical operational modes: a) base ring anchored embedment (encapsulation) into the polyethylene of the fuel tank, b) base ring strength during fuel tank flex, and c) base ring strength during lock ring installation.

The tangential length of the lock ring finger apertures is designed to only allow a 1 degree of over-travel before a “dead stop” occurs.

The shape, position, arc length, radius, and number of bossed service tool boss interface notches 148 of the lock ring 122 are a balance between five critical factors: a) need for interfacing with the bossed service tool, b) need for the bossed service tool to provide lock ring installation (“camming on”), c) need for the bossed service tool to effect removal of the lock ring (“camming off”), d) elimination of inclusion of a stress riser, thus preventing ring potato chipping, and e) multiple bossed service tool orientation options.

While the aforementioned prior art sender module closure system 100 has provided exemplar service, it would be very beneficial if somehow it could be strengthened and provide protection for the sender module while yet being able to be interfaced as described above by the bossed service tool.

SUMMARY OF THE INVENTION

The present invention is an improved sender module closure system for providing a reliable, sealed interface between the sender module and the fuel tank at the access port thereof, wherein the improvement resides in the lock ring thereof, wherein the conventional lock ring is replaced by a helmeted lock ring so as to provide, among a range of attributes, strength and protection for the sender module.

The improved sender closure module system according to the present invention includes a mutually interfacing ring set composed of a base ring and a helmeted lock ring.

The base ring is conventional, being permanently connected to the fuel tank at the access port, as for example by encapsulation of an anchor portion thereof by the polyethylene of the fuel tank during its manufacture. The base ring has a plurality of upstanding lock fingers spaced equally therearound, each lock finger having a lip. Each lip has a prestage ramp, a staging boss, a staging socket and an over-travel boss.

The helmeted lock ring is a separate piece, composed of a lock ring component and a helmet component.

The lock ring component is configured to mimic a conventional lock ring, having a plurality of finger apertures, one for receiving each lock finger. Each finger aperture has an entry portion for passing a respective lock finger therethrough and a lock portion at which the lip interferingly overhangs a lock shelf of the lock ring member. Each lock shelf adjoins the lock portion of its corresponding finger aperture, and has a medially located lock boss.

The helmet component is connected with the lock ring component at the inner periphery thereof, preferably integrally as a single piece construction. The helmet component is composed of a helmet sidewall in upstanding relation to the lock ring component at the inner periphery thereof, and a helmet cover wall integrally formed with the helmet sidewall. One or more helmet apertures are formed in the helmet component to provide access for components of the sender module and yet provide a protective covering of the sender module.

In operation, as is the conventional practice known in the art, the periphery of the access port of the fuel tank has a seal seat groove which is concentrically disposed relative to the lock fingers. A resilient seal is located at the seal seat groove. The sender module is located at the access port, wherein an annular flange of the sender module rests upon the resilient seal.

Now, according to the present invention, the helmeted lock ring is placed over the sender module so that the components of the sender module have access through the one or more helmet apertures. The finger apertures of the lock ring component now receive the lock fingers, and the helmeted lock ring is thereafter rotated by hand or with use of a bossed service tool so that each lock shelf is prestaged interferingly under its respective lock finger prestage ramp. The conventional bossed service tool is then used to rotate the helmeted lock ring so that each lock boss slides along its respective staging boss and then seats at its respective staging socket. As each lock boss slides along its staging boss and then seats in its staging socket, the helmeted lock ring is moved toward the fuel tank, which movement causes the resilient seal to be compressed sealingly between the fuel tank at the seal seat groove and the annular flange of the sender module. Over-travel is not permitted by the lock finger abutting the end of its respective finger aperture, and each lock boss tends to center at its staging socket by cooperative action of the over-travel and staging bosses with respect to the lock boss situated therebetween. Now the sender module is protected by the helmet component, and the helmeted lock ring has strength to resist shears and forces as may be at some later time applied to the improved sender module closure system.

Accordingly, it is an object of the present invention to provide an improved sender module closure system for providing a reliable, sealed interface between the sender module and the fuel tank at the access port thereof, wherein the improvement resides in a helmeted lock ring which provides, among various attributes, inherent strength as well as protection for the sender module.

This and additional objects, features and advantages of the present invention will become clearer from the following specification of a preferred embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a fuel tank, showing a sender module sealingly interfaced thereto by a prior art sender module closure system.

FIG. 2 is a broken-away partly sectional side view of the prior art sender module closure system interfaced with the fuel tank and sender module as in FIG. 1.

FIG. 3 is a perspective view of a base ring of a ring set according to the prior art sender module closure system.

FIG. 4 is a perspective view of a lock ring of the ring set according to the prior art sender module closure system.

FIG. 5 is a top plan view of the base ring of FIG. 3.

FIG. 6 is a side view of the base ring, seen along line 6-6 of FIG. 5.

FIG. 7 is a detail top view of a lock finger of the base ring of FIG. 3, seen at circle 7 of FIG. 5.

FIG. 8 is a partly sectional, broken away view, seen along line 8-8 of FIG. 5.

FIG. 9 is a top plan view of the prior art lock ring of FIG. 4.

FIG. 10 is a side view of the prior art lock ring, seen along line 10-10 of FIG. 5.

FIG. 11 is a detail sectional view, seen along line 11-11 of FIG. 9.

FIG. 12 is a sectional, broken away view showing a lock boss of the prior art lock ring seated at its respective staging socket of a lock finger of the base ring.

FIG. 13A is a first operational view, depicting a lock boss prestaged on its respective prestage ramp.

FIG. 13B is a second operational view, depicting the lock boss now seated at its respective staging socket.

FIG. 14 is a perspective view of the prior art lock ring interferingly interfaced with the base ring.

FIG. 15 is a partly sectional top plan view of a lock finger interferingly located at a lock shelf adjacent the lock portion of its respective finger opening according to the prior art sender module closure system.

FIG. 16 is a perspective view of an improved sender module closure system having a helmeted lock ring according to the present invention.

FIG. 17 is a top plan view of the improved sender module closure system, wherein the improvement resides in a helmeted lock ring according to the present invention.

FIG. 18 is a broken-away partly sectional side view of the improved sender module closure system with helmeted lock ring according to the present invention interfaced with a fuel tank and a sender module.

FIG. 19 is a partly sectional top plan view of a lock finger interferingly located at a lock shelf adjacent the lock portion of its respective finger opening of the improved sender module closure system having a helmeted lock ring according to the present invention.

FIG. 20A is a first operational view, depicting a lock boss prestaged on its respective prestage ramp of the improved sender module closure system having a helmeted lock ring according to the present invention.

FIG. 20B is a second operational view, depicting the lock boss now seated at its respective staging socket of the improved sender module closure system having a helmeted lock ring according to the present invention.

FIGS. 21A and 21B are perspective views showing a bossed service tool being interfaced with notches of the helmeted lock ring according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is a helmeted lock ring 222, as shown at FIGS. 16 through 21B, which is structured to replace the hereinabove described prior art lock ring 122 to thereby improve the hereinabove described sender module closure system 100. In this regard, the helmeted lock ring 222 has a lock ring component 222R which is structurally and functionally the same as the aforementioned prior art lock ring 122, wherein one may be substituted for the other in the aforesaid sender module closure system. Therefore, the description hereinabove with respect to FIGS. 1 through 15 is applicable to the lock ring component 222R exactly as it is applicable to the prior art lock ring 122, so that the description and reference to FIGS. 1 through 15 in the hereinabove Background of the Invention is fully applicable to the structure and function of the lock ring component 222R with respect to the sender module closure system 100. Accordingly, like components and features as discussed hereinabove will be designated hereinbelow using the same numerals used in FIGS. 1 through 15.

The lock ring component 222R of the helmeted lock ring 222 has a plurality of finger apertures 142, one for receiving each lock finger 124 (see FIG. 19). Each finger aperture 142 has an entry portion 142E for passing a respective lock finger 124 therethrough and a lock portion 142L at which the lip 126 of the respective lock finger interferingly overhangs a lock shelf 144 of the lock ring component 222R. Each lock shelf 144 tangentially adjoins the lock portion 142L of its corresponding finger aperture 142, and has a medially located lock boss 146.

A helmet component 222H of the helmeted lock ring 222 is connected with the lock ring component 222R, preferably integrally as a single piece construction. In this regard, a helmet sidewall 250 connects to the inner periphery 152 of the lock ring component 222R. A helmet cover wall 260 is integrally connected with the helmet sidewall 250 in generally perpendicular relation to the helmet sidewall (ie., parallel to the orientation of the lock ring component). One or more helmet apertures 270 are provided in the helmet component 222H, provided in the helmet cover wall, the helmet sidewall or both the helmet cover wall and sidewall, so as to allow external access to components 280 of the sender module 104. An upstanding lug 240 (which may be low-rise or high-rise depending on the placement of the helmet aperture) spans each of the helmet apertures formed in the helmet sidewall at the inner periphery 152 of the lock ring component 222R.

Operationally, in analogous manner to that respecting FIGS. 1 through 15, the sender module 104 is placed into the access port 106 such that the periphery thereof abuts the annular lip 116. With the resilient seal 110 seated at its seal seat groove 108, and the annular flange 114 resting upon the resilient seal, the helmeted lock ring 222 is placed thereover, wherein the helmet aperture or apertures 270 provide external access to the sender module components 280. Now, the lock fingers 124 are received through the entry portion 142E of the finger apertures 142. The helmeted lock ring 122 is then rotated so that the flat 144F of each lock shelf 144, as shown by FIG. 20A, is prestaged interferingly under its respective lock finger prestage ramp 128. As can be understood from FIGS. 21A and 21B, the outer perimeter 122P of the lock ring component 222R has a plurality of tool engagement features in the preferred form of notches 148 into which are interfaced with bosses 154 a of a bossed service tool 154 so as to effect the aforesaid rotation and/or to effect further rotation of the helmeted lock ring 222 relative to the base ring 120. In this regard, as best shown at FIG. 21, the conventional bossed service tool 154 is able to interface with the lock ring component 222R and avoid interfering contact with the helmet component 222H. The service sequence normally involves removal of hoses (at quick-connects) and wiring (at harness connectors), then installation/removal of the helmeted lock ring.

As the rotation ensues (referred to as “camming on”), each lock boss 146 slides along its respective staging boss 130 and seats at its respective staging socket 132, as shown at FIG. 20B. The seating of the lock bosses 146 in the respective staging sockets 132 causes the lock ring 122 to move toward the fuel tank 102 (in the manner progressively shown by FIGS. 20A and 20B). Accordingly, as shown at FIG. 18, the resilient seal 110 is compressed (ie., a compression of about 25 percent) so as to cause the resilient seal to seal between the floor of the seal seat groove 108 and the annular flange 114 of the sender module 104. Over-travel is not permitted by the lock finger 124 abutting the end 142S, as shown at FIG. 19, of its respective finger aperture 142, and each lock boss 146 tends to center at its staging socket 132 by cooperative action of the over-travel boss 134 and the staging boss 130 with respect to the lock boss 146 situated therebetween. Subsequently, the bosses 154 a of the bossed service tool 154 may be again interfaced with the notches 148 so as to effect reverse rotation of the helmeted lock ring 222 (referred to as “camming off”) so that the sender module 104 may be removed from the fuel tank 102.

When the helmeted lock ring 222 is cammed on into the staged position, a “ball and socket” arrangement transpires, entailing a critical manufacturing of both a 2.5 mm radius “socket” and a 2.0 mm radius “ball.” The entire load dissipation of the ring set composed of the base ring and the helmeted lock ring, at the staged position occurs through the seven lock bosses which are equally spaced apart by 53.4 degrees (also referred to as “top dead center” of the “ball” locking into the “socket”), wherein the critical linear load carrying distance for this interface is 4.0 mm radially inward from the lock portion 142L of the finger aperture. To ensure maximum load transfer between the lock ring component 222R and the lock fingers 124, the lock ring finger apertures are toleranced and narrowed so as to be as small as possible.

As mentioned hereinabove with respect to the base ring, the shape of the lock fingers is a balance between three critical items: a) maximum strength, b) the allowance for an anti-reverse rotation feature, and c) the allowance for a “solid” discernable stop. Further, the “offset” W-shape associated with the staging boss, staging socket and over-travel boss of the lips is provided by two post-strikes which are put in during the finalization of the part, wherein a “lead” strike provides the staging boss, and a “follow” strike provides the over-travel boss, and wherein the position of these features relative to the center of the lip allows for two 17 to 18 degree angles which increase strength due to material processing.

One function of the helmeted lock ring 222 is to serve as a lock ring in the manner of the prior art lock ring 122, while another function is to provide a protective shield for the sender module 104, inclusive of its component interfaces.

There are a number of concerns with regard to vehicle architecture vis-a-vis the sender module closure system. These concerns include: a) the vehicle body or underbody components adversely contacting the sender module, and/or damaging external connectors of the sender module during a crash event; b) certain crash events possibly involving situations in which a crash pulse and liquid response dynamics of the fuel tends to force the sender module toward the vehicle underbody; c) certain crash pulses possibly creating a torque in the area of the sender module which tends to cause “bottle cap” opening of the interface between the flange and the seal; d) certain crash events possibly involving folding of the fuel tank across the sender module and involving the fuel tank access port; e) certain crash events possibly causing the sender module access port of the fuel tank being distorted in the horizontal plane (ovality); and f) certain crash events possibly causing the vehicle underbody to fold down onto the sender module access opening in the fuel tank. Any of these untoward events can cause, for example, a crack in the sender module flange or cause a momentary relief of seal compression between the seal, the flange, and/or the fuel tank groove.

These vehicle architecture concerns may be assuaged by the sender module closure system including the helmeted lock ring 222, as discussed hereinbelow.

For reference, the criteria for strength of the helmeted lock ring are: a) providing uniform vertical “pull up” strength evenly distributed through the seven equally spaced load transfer points of the lock finger and lock boss interface locations; b) providing horizontal ring displacement with respect to the helmeted lock ring with respect to the base ring, so as to distribute load displacements through same load centerline; c) providing vertical “push down” of the lock ring component to prevent “kink down” between the encapsulated ring tabs; and d) providing helmet component structural integrity against collapse.

There are a number of documented critical features of the helmeted lock ring when simultaneously incorporated in a sender module closure system, as follows.

1. A helmeted lock ring material thickness of between 3.0 and 2.4 mm is required. A material thicker than this cannot be formed to achieve the dimensional tolerances required, and if thinner, the material will be weaker in kink resistance.

2. The material type selected (Galvannealed per GMW2M-ST-S-CR1C) is extremely critical to helmeted lock ring strength and durability. The critical sub-component of the material is carbon percentage.

3. The helmeted lock ring primary “engagement” to its mating part (i.e., the base ring) occurs through the “top dead center” of the seven equally spaced load transfer points of the lock finger and lock boss interface locations. The actual radial engagement is 3.75+/−0.50 mm. Smaller dimensions than this run the risk of “disengagement” due to lateral (radial) movements of the ring set (i.e., offset of the ring centerlines). Any dimension larger than this, and the risk of “false torque stalls” exists during ring set tightening (i.e., inability of the bossed service tool to install the helmeted lock ring).

4. The helmeted lock ring is a one-piece lock ring and helmet components combination. The deep drawn helmet component has three purposes. The first purpose is to function as a secondary piloting feature for the sender module. The second purpose is to add significant kink resistance to the lock ring component in both vertical directions. The third purpose is to shield against sender unit crush due to contact with the underbody or displacement caused by an external load, such as might occur during a crash.

5. The helmeted lock ring interfaces with the base ring at the seven equally spaced load transfer points of the lock finger and lock boss interface locations. The interfacing shapes and how each is formed is critical. Each interface location has four unique attributes which provide strength, durability, and the perception of “lock-up engagement”. The first feature is the “prestage”, involving the “landing area” where the ring set temporarily sits before final lock-up, whereat rotation of the helmeted lock ring can be accomplished manually. The second attribute is the “cam ramp”, wherein the angle of the ramp is a balance between smooth torque transition, amount of rotation required before “lock-up”, and the ability to process the material. The third attribute is referred to as the “top dead center” of the interface locations, whereat the ring set officially “locks-up”, wherein to further add strength and ensure the interface locations do not get “washed-out” a 2.0 mm. “post-coin” operation is added. The fourth attribute is referred to as the “over-travel” stop, which is the primary structural aspect preventing the helmeted lock ring from “over caming” past the “top-dead center” lock-up.

6. The anticipated torque loads handled by the helmeted lock ring is expected to be on the order of 300 ft/lbs. To withstand this torque without interface location “collapse” or “washout” each interface location has been transitioned into the ring inner periphery at the helmet sidewall.

7. During the “cam over” process, a tremendous amount of force exists. If the ring set slips over the “top dead center” and gets lodged, then the helmeted lock ring will be in a position in which there is an inappropriate sender module seal compression. Therefore, to prevent this “over cam” from happening, a secondary stop has been built into the helmeted lock ring.

8. The helmeted lock ring interfaces as described hereinabove with the encapsulated base ring. To lock the helmeted lock ring to the base ring requires a relative rotation of about twelve degrees. To achieve maximum strength, the lock portion of the finger apertures of the helmeted lock ring in which the lock fingers of the base ring relatively travel has been narrowed. This width accommodates a 2.0 mm thick base ring. Narrowing the finger apertures may increase strength but will provide for the opportunity of “cam binding”. Increasing will allow the base ring to shift relative to the helmeted lock ring, thus resulting in a non-uniform load distribution.

9. The helmeted lock ring is a separate component of the sender module closure system which needs to be installed and removed. This operation is typically conducted by usage of a bossed service tool and, for example, a manufacturing tool. In addition, the helmet component has, for example, three specific helmet apertures in areas that offer the maximum protection without sacrificing strength. The electrical component access portion of the helmet apertures are, for example, formed through the helmet sidewall. The service sequence is to take the connectors off first and then install/remove the helmeted lock ring. The fuel line component access portion of the helmet apertures are, for example, formed in the helmet sidewall and cover wall. The service sequence is to remove the quick connects and then install/remove the helmeted lock ring.

10. An important structural consideration is that the helmeted lock ring be a one piece design which is targeted to fit all sender modules, both in terms of improved strength and reduced assembly cost.

To those skilled in the art to which this invention appertains, the above described preferred embodiment may be subject to change or modification. For example, the base ring could be adapted to attach to a metal fuel tank. Such change or modification can be carried out without departing from the scope of the invention, which is intended to be limited only by the scope of the appended claims. 

1. In a sender module closure system comprising: a fuel tank having an access port; a base ring connected to said fuel tank in concentric relation to said access port, said base ring having a plurality of upstanding lock fingers spaced therearound, each lock finger having a laterally oriented lip, each said lip having a staging socket; a sender module having connectors and an annular flange; and a resilient seal disposed between said fuel tank and said annular flange; the improvement thereto comprising: a helmeted lock ring comprising: a lock ring component having an inner periphery, said lock ring component having a plurality of finger apertures, one finger aperture respectively for each said lock finger, said lock ring component having a plurality of lock bosses, a lock boss being respectively located adjacent each said finger aperture; and a helmet component comprising a helmet sidewall connected to said inner periphery of said lock ring component in upstanding orientation with respect thereto, and a helmet cover wall connected to said helmet sidewall in generally perpendicular orientation with respect thereto, said helmet component having at least one helmet aperture formed therein for external access to said connectors of said sender module; wherein each said lock finger is received through a respective finger aperture, whereupon said helmeted lock ring is rotated relative to said base ring until each said lock boss is seated into a respective staging socket, said rotation causing said lock ring component to press upon said annular flange so as to compress said resilient seal into sealing relation with respect to said fuel tank and said annular flange.
 2. The system of claim 1, further comprising a lug at said inner periphery of said lock ring component spanning each said helmet aperture which is formed in said helmet sidewall; wherein said helmeted lock ring is a single piece construction, wherein said helmet sidewall is integrally connected to said lock ring component, and said helmet cover wall is integrally connected to said helmet sidewall.
 3. The system of claim 2, wherein each said lip further has a prestage ramp, a staging boss disposed between said prestage ramp and said staging socket and an over-travel boss adjoining said staging socket in opposed disposition with respect to said staging boss.
 4. The system of claim 3, wherein each said finger aperture comprises an entry portion configured for passing therethrough said lock finger and a lock portion; and wherein said lock ring component has a plurality of lock shelves, one lock shelf respectively for each finger aperture, wherein each lock shelf tangentially adjoins its respective said lock portion, each said lock boss being disposed on a respective lock shelf.
 5. The system of claim 4, wherein each said lock shelf radially adjoins its respective entry portion, a flat being formed between the radially adjoining entry portion and the respective lock boss.
 6. The system of claim 5, wherein each said lock portion has an end which defines a maximum rotation of said lock ring component with respect to said base ring when the lock finger respectively therein abuts the end; wherein said maximum rotation coincides with each said lock boss engaging its respective over-travel boss.
 7. The system of claim 6, further comprising a bossed service tool having a plurality of bosses; wherein said lock ring component further comprises tool engagement features disposed at an outer perimeter thereof, wherein the helmeted lock ring is rotatable by assistance of the bossed service tool when the bosses thereof are engaged with said engagement features.
 8. The system of claim 7, wherein said plurality of lock fingers comprises seven lock fingers equally spaced around said base ring.
 9. The system of claim 8, wherein each said lip faces radially inward toward a center of said base ring.
 10. The system of claim 9, wherein said base ring further comprises an anchor portion which is anchorably embeded in said fuel tank.
 11. A ring set for a sender module closure system, said ring set comprising: a base ring having a plurality of upstanding lock fingers spaced therearound, each lock finger having a laterally oriented lip, each said lip having a staging socket, a prestage ramp, a staging boss disposed between said prestage ramp and said staging socket and an over-travel boss adjoining said staging socket in opposed disposition with respect to said staging boss; and a helmeted lock ring comprising: a lock ring component having an inner periphery, said lock ring component having a plurality of finger apertures, one finger aperture respectively for each said lock finger, said lock ring component having a plurality of lock bosses, a lock boss being respectively located adjacent each said finger aperture; and a helmet component comprising a helmet sidewall connected to said inner periphery of said lock ring component in upstanding orientation with respect thereto, and a helmet cover wall connected to said helmet sidewall in generally perpendicular orientation with respect thereto, said helmet component having at least one helmet aperture formed therein, wherein a lug located at said inner periphery spans each said helmet aperture which is formed in said helmet sidewall; wherein each said lock finger is received through a respective finger aperture, whereupon said helmeted lock ring is rotated relative to said base ring until each said lock boss is seated into a respective staging socket, said rotation causing said lock ring component to move toward said base ring.
 12. The ring set of claim 11, wherein said helmeted lock ring is a single piece construction, wherein said helmet sidewall is integrally connected to said lock ring component, and said helmet cover wall is integrally connected to said helmet sidewall.
 13. The ring set of claim 12, wherein each said finger aperture comprises an entry portion configured for passing therethrough said lock finger and a lock portion; and wherein said lock ring component has a plurality of lock shelves, one lock shelf respectively for each finger aperture, wherein each lock shelf tangentially adjoins its respective said lock portion, each said lock boss being disposed on a respective lock shelf; and wherein each said lock shelf radially adjoins its respective entry portion, a flat being formed between the radially adjoining entry portion and the respective lock boss.
 14. The ring set of claim 13, wherein each said lock portion has an end which defines a maximum rotation of said helmeted lock ring with respect to said base ring when the lock finger respectively therein abuts the end; and wherein said maximum rotation coincides with each said lock boss engaging its respective over-travel boss.
 15. The ring set of claim 14, wherein said plurality of lock fingers comprises seven lock fingers equally spaced around said base ring; wherein each said lip faces radially inward toward a center of said base ring; wherein said lock ring component further comprises tool engagement features disposed at an outer perimeter thereof; and wherein said base ring further comprises an anchor portion.
 16. A helmeted lock ring for a sender module closure system, comprising: a lock ring component having an inner periphery, said lock ring component having a plurality of finger apertures, said lock ring component having a plurality of lock bosses, a lock boss being respectively located adjacent each said finger aperture; and a helmet component comprising a helmet sidewall connected to said inner periphery of said lock ring component in upstanding orientation with respect thereto, and a helmet cover wall connected to said helmet sidewall in generally perpendicular orientation with respect thereto, said helmet component having at least one helmet aperture formed therein, wherein a lug located at said inner periphery spans each helmet aperture which is formed in said helmet sidewall.
 17. The helmeted lock ring of claim 16, wherein said helmeted lock ring is a single piece construction, wherein said helmet sidewall is integrally connected to said lock ring component, and said helmet cover wall is integrally connected to said helmet sidewall.
 18. The helmeted lock ring of claim 17, wherein each said finger aperture comprises an entry portion and a lock portion; and wherein said lock ring component has a plurality of lock shelves, one lock shelf respectively for each finger aperture, wherein each lock shelf tangentially adjoins its respective said lock portion, each said lock boss being disposed on a respective lock shelf; and wherein each said lock shelf radially adjoins its respective entry portion, a flat being formed between the radially adjoining entry portion and the respective lock boss. 